Autor(es)

Olivetti Estevam da Silva, Leandro ; Silva, Lais Dantas ; Zanotto, Edgar Dutra ; de Oliveira Junior, Marcos ; Manzani, Danilo

• Tipo de documento: Artigo Científico
• Fonte: ACS OMEGA; v. N/A, p. 17-pg., 2025-09-26.

Resumo

Niobium-fluorophosphate glasses show promising technological and scientific potential in a wide range of optical and photonic applications due to their properties as a host matrix, such as wide transparency between the ultraviolet and near-infrared, high solubility to rare-earth ions, low phonon energy, and high chemical stability. Efforts were previously made to study the effects that different concentrations of niobium oxide have on the base phosphate glass composition used here in the structural, thermal, and optical properties. However, an exploration of which changes different alkaline earth metals can induce in niobium-phosphate glass properties, considering their modifying role and periodic properties, is lacking. Therefore, this study aimed to thoroughly investigate how different alkaline earth metals can induce variations in the structural, thermal, and optical properties of a novel niobium-phosphate glass. The tested glasses followed the compositional rule (80 - y)NaPO3-yNb2O5-20XF2 (X = Mg2+, Ca2+, Sr2+, Ba2+, y = 5, 10, 15, 20 mol % of Nb2O5) and were synthesized by the melt-quenching method. Analysis by differential scanning calorimetry (DSC), UV-vis absorption spectroscopy, and optical bandgap calculations shows that the covalent character of the glass matrix increases for increasing Nb2O5 content, causing an increase in the glass transition temperature, T g, and a decrease of the optical bandgap energy. DSC analyses revealed a very high stability against crystallization, Delta T up to nearly 400 degrees C (Delta T = T x - T g)-where T x is the crystallization peak temperature-for this glass-forming system. 31P NMR experiments revealed that the increase in Nb2O5 between 5 and 15 mol % induced the formation of P0, P1Nb 1, and P2Nb 2 phosphate units, consequently increasing the glass matrix connectivity due to the formation of P-O-Nb and Nb-O-Nb bonds. Moreover, 19F nuclear magnetic resonance showed how the alkaline earth metals with a higher charge-to-radius ratio (smaller ionic radius) preferentially bond with the fluoride species within the glass matrix. Consequently, the glass connectivity increases due to the lower availability of fluoride to interact with the main glass former groups (i.e., phosphate and niobate groups). (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 22/01762-0 - Influência de fluoretos de alcalinos terrosos (MgF2, CaF2, SrF2, BaF2) e Nb2O5 nas propriedades estruturais e ópticas em vidros fluorofosfoniobatos
• Beneficiário: Leandro Olivetti Estevam da Silva
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 19/16115-8 - Estudo das propriedades ópticas e luminescentes de vidros e vitrocerâmicas fluorofosfatos contendo fluoretos de alcalinos terrosos (MgF2, CaF2, SrF2, BaF2) e dopados com íons lantanídeos
• Beneficiário: Leandro Olivetti Estevam da Silva
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 23/05994-6 - Conversão de energia envolvendo íons lantanídeos em vidros e vitrocerâmicas oxifluoretos: Dos estudos fundamentais às propriedades luminescentes e termométricas
• Beneficiário: Danilo Manzani
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 23/09794-1 - Estudo espectroscópico e estrutural de vidros e vitrocerâmicas fluorofosfoniobatos contendo metais alcalinos terrosos dopados com Eu3+ e codopados com Yb3+/Tm3+
• Beneficiário: Leandro Olivetti Estevam da Silva
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
• Processo FAPESP: 24/17334-3 - Redes metal-orgânicas vítreas de lantanídeos: Síntese e caracterização espectroscópica
• Beneficiário: Leandro Olivetti Estevam da Silva
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 21/08111-2 - Materiais conversores de luz à base de terras raras: marcadores luminescentes, sensores e amplificadores ópticos
• Beneficiário: Hermi Felinto de Brito
• Modalidade de apoio: Auxílio à Pesquisa - Temático